[ Upstream commit
cb3ea4b7671b7cfbac3ee609976b790aebd0bbda ]
We don't set it on PF_KTHREAD threads as they never return to userspace,
and PF_IO_WORKER threads are identical in that regard. As they keep
running in the kernel until they die, skip setting the FPU flag on them.
More of a cosmetic thing that was found while debugging and
issue and pondering why the FPU flag is set on these threads.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/560c844c-f128-555b-40c6-31baff27537f@kernel.dk
Signed-off-by: Sasha Levin <sashal@kernel.org>
static inline void switch_fpu_prepare(struct fpu *old_fpu, int cpu)
{
if (cpu_feature_enabled(X86_FEATURE_FPU) &&
- !(current->flags & PF_KTHREAD)) {
+ !(current->flags & (PF_KTHREAD | PF_IO_WORKER))) {
save_fpregs_to_fpstate(old_fpu);
/*
* The save operation preserved register state, so the
struct fpu *fpu = ¤t->thread.fpu;
int cpu = smp_processor_id();
- if (WARN_ON_ONCE(current->flags & PF_KTHREAD))
+ if (WARN_ON_ONCE(current->flags & (PF_KTHREAD | PF_IO_WORKER)))
return;
if (!fpregs_state_valid(fpu, cpu)) {
this_cpu_write(in_kernel_fpu, true);
- if (!(current->flags & PF_KTHREAD) &&
+ if (!(current->flags & (PF_KTHREAD | PF_IO_WORKER)) &&
!test_thread_flag(TIF_NEED_FPU_LOAD)) {
set_thread_flag(TIF_NEED_FPU_LOAD);
save_fpregs_to_fpstate(¤t->thread.fpu);